LONDON (AFP) - Prince William's second child, due later this month, will be born fourth in line to inherit the British throne, behind their first child Prince George.
Everyone below the new royal baby will move down a place, starting with William's brother Prince Harry who will drop to fifth position.
The immediate line of succession to the throne includes Queen Elizabeth II's four children and their offspring:
1. PRINCE CHARLES, PRINCE OF WALES - Born 1948. Eldest son of Queen Elizabeth.
2. PRINCE WILLIAM, DUKE OF CAMBRIDGE - Born 1982. Charles' eldest son.
3. PRINCE GEORGE OF CAMBRIDGE - Born 2013. William's son.
4. PRINCE HENRY OF WALES - Born 1984. Charles' second son.
5. PRINCE ANDREW, DUKE OF YORK - Born 1960. Queen Elizabeth's second son.
6. PRINCESS BEATRICE OF YORK - Born 1988. Andrew's eldest daughter.
7. PRINCESS EUGENIE OF YORK - Born 1990. Andrew's second daughter.
8. PRINCE EDWARD, EARL OF WESSEX - Born 1964. Queen Elizabeth's third son.
9. JAMES, VISCOUNT SEVERN - Born 2007. Edward's son.
10. LADY LOUISE WINDSOR - Born 2003. Edward's daughter.
11. PRINCESS ANNE, PRINCESS ROYAL - Born 1950. Daughter of Queen Elizabeth.
12. PETER PHILLIPS - Born 1977. Anne's son.
13. SAVANNAH PHILLIPS - Born 2010. Phillips' eldest daughter.
14. ISLA PHILLIPS - Born 2012. Phillips' second daughter.
15. ZARA TINDALL - Born 1981. Anne's daughter.
16. MIA TINDALL - Born 2014. Zara Tindall's daughter.
Queen Elizabeth's descendants are followed by those of her late sister princess Margaret, her only sibling.
The offspring of their father king George VI's siblings then follow, with more than 60 living people descended from his father king George V, who died in 1936.
The monarchy's website lists only the first 15 people in line, though some extensive counts reach around 2,000 people eligible to inherit.
Drawn up in an era of religious strife, the Act of Settlement 1701, which sets out the succession laws, states that only Protestant descendants of Sophia of Hanover, the mother of king George I, can accede to the throne.
Some counts list more than 5,700 living descendants of Sophia, including Roman Catholics who cannot inherit.
The highest person excluded on these grounds is 26-year-old Edward Windsor, Lord Downpatrick, a first cousin twice removed of the queen, who converted to Catholicism. He would otherwise be 35th in line.
A change to the succession laws which came into effect last month means males born after October 28, 2011 no longer take precedence over their older sisters.
Also people married to Catholics are no longer excluded, with Downpatrick's father George Windsor, the Earl of St Andrews, being restored to the line in 34th place.
The line is a vast tangle of nobility and ordinary, untitled descendants from all corners of Europe.
Several other European monarchs feature, led by King Harald V of Norway - who is in the first 100 - King Carl XVI Gustaf of Sweden and Queen Margrethe II of Denmark, who are within the first 400.
Besides Britain, it is also the line of succession to the thrones of Antigua and Barbuda, Australia, The Bahamas, Barbados, Belize, Canada, Grenada, Jamaica, New Zealand, Papua New Guinea, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Solomon Islands and Tuvalu.